Pacific Gas and Electric Co. dismissed nearly all of state utility regulators' accusations of wrongdoing stemming from the 2010 San Bruno gas-pipeline explosion as an exercise in scapegoating, as the state opened a hearing Tuesday that could lead to hundreds of millions of dollars in fines against the company.

"It's human nature when bad things happen to look for someone to blame - and make no mistake about it, that is what this proceeding is all about," PG&E lawyer Joseph Malkin said in opening remarks before an administrative law judge in San Francisco, who will recommend whether the utility should be fined for the Sept. 9, 2010, explosion that killed eight people and destroyed 38 homes.

"While PG&E acknowledges that it is responsible for this terrible accident and its consequences," Malkin said, "it does not agree that once that pipe was put in the ground in 1956 there was anything any operator would reasonably have done that would have prevented this tragedy. Nor does PG&E agree that any of the alleged safety violations contributed in any way."

The administrative law judge, Mark Wetzell, will make determinations on the allegations and recommend action to the five-member Public Utilities Commission. The panel will make the final decision on the size of any fine against PG&E.

The company is accused by state regulators of violating industry standards when it installed the San Bruno pipe. PG&E failed to perform strength tests, used metal weaker than its own standards called for and held the pipe together with defective welds, the commission's staff said in a report.

The staff has also said PG&E's pipeline integrity management program, record keeping and emergency response the night of the blast violated the law. In particular, the company was accused by regulators of failing to test the San Bruno line in recent years even after it twice boosted gas pressures above legal levels.

PG&E has said its spiking was legal, posed no danger to the pipeline and had nothing to do with the blast. It has suggested that it in fact did test the line, based on the recollection of one of its former workers.

Tony Earley, PG&E's chief executive officer, has recently said the company "lost its way" before he arrived in 2011, but the company's lawyer suggested otherwise. Malkin said PG&E's only responsibility in the blast was unwittingly installing and operating a defective pipe.

Attorneys for the cities of San Bruno and San Francisco, which are both participants in the hearing, said PG&E had been reckless in its pipeline operations.

Austin Yang, a deputy city attorney for San Francisco, said the blast was the product of "systemic and ongoing dysfunction at PG&E," while Steven Meyers, an attorney for San Bruno, accused the company of being "grossly negligent."

Malkin countered that most of the commission staff allegations involved PG&E actions that were consistent with industry standards. In the few instances in which the company may have violated state law or regulations, he said, the actions had nothing to do with causing the disaster.

"PG&E does not claim that its past practices have been perfect," Malkin said. "But the most serious of (commission staff) allegations are simply not true, and none of those shortcomings was responsible in any way for the San Bruno accident."